Most internal combustion engines convert the chemical energy of a fuel source, such as gasoline, to thermal energy, and in turn, convert the thermal energy to mechanical energy, utilizing a thermodynamic cycle, such as a form of an Otto cycle. While the Otto cycle is theoretically an idealized cycle, actual engines operate using the same four basic stages, namely, (1) intake of fuel and air, (2) compression of the fuel-air mixture, (3) combustion of the fuel and air causing expansion, (4) and exhaust of the products of combustion. In a reciprocating piston-type engine, these four stages are often equated with the four strokes of each piston to complete a full cycle, and are called (1) the intake stroke, (2) the compression stroke, (3) the power stroke (expansion following combustion), and (4) the exhaust stroke. Thus, the name “four-stroke” engine for the most commonly used internal combustion engine. Such engines are used in many automobiles and other vehicles, such as aircraft and marine craft, as well as industrial engines, stationary power plants, and small engine applications such as lawn mowers.
In many applications of piston-type, four-stroke engines, the reciprocating linear motion of the pistons is translated to rotational motion using piston rods and linkages to a crankshaft. In an automobile, for example, the crankshaft is then coupled to a flywheel, and the other end of the flywheel shaft is coupled to the transmission.
Rotary-type engines have also been developed which operate using the Otto cycle and its four stages. For instance, the Wankel rotary engine is probably the best known and most commonly used rotary internal combustion engine. Various Wankel rotary engine designs are described in U.S. Pat. Nos. 2,988,065; 3,918,413; 3,987,758, as examples. The contents of each of these patents is expressly incorporated by reference herein in their entireties. Generally, the Wankel rotary engine utilizes a housing having an epitrochoid interior wall (oval-like) and a rotor within the housing. The rotor has a triangular shape with convex curved sides. The space between the three sides of the rotor and the inside surface of the housing creates three separate cavities. The rotor is supported by an eccentric shaft which passes through the interior of the rotor at a location displaced from the geometric center of a cross-section of the rotor. The rotor both rotates and orbitally revolves around the eccentric shaft. The motion (rotation and orbital revolution) of the rotor is controlled by a pair of synchronizing gears. An internal ring gear attached to the rotor engages a fixed spur gear mounted to the housing. The gears cause the rotor to revolve ⅓ of a rotation around the housing for each turn of the eccentric shaft.
As the rotor rotates and orbitally revolves, the three sides of the rotor move closer to and then away from the interior wall of the housing thereby compressing and expanding the three cavities, similar to the strokes of a piston in a reciprocating engine. Each cavity of the Wankel rotary engine experiences one combustion stroke for each driveshaft rotation. In other words, one cavity completes the four strokes of the Otto cycle for each orbital revolution of the rotor, and each of the three cavities completes an Otto cycle for each full rotation of the rotor.
There are a number of other types of internal combustion engines that have been developed. For example, internal combustion engines have been developed based on a two-stroke cycle or a six-stroke cycle. Some internal combustion engines operate on the Brayton cycle as opposed to the Otto cycle, such as gas turbines, jet engines, turboprops and the like. There are also compression ignition engines, also known as diesel engines.
Internal combustion engines are commonly used for mobile propulsion in vehicles and portable machinery because of their ability to attain high power-to-weight ratios in addition to excellent fuel energy density. Generally using fossil fuel (mainly petroleum), these engines have appeared in transport in almost all types of vehicles, including automobiles, trucks, motorcycles, boats, and in a wide variety of aircraft and locomotives.
While a variety of engines have been previously developed, the prior art does not disclose or suggest an engine according to the present invention.